Integrated elastomeric lipseal and cup bottom for reducing wafer sticking

ABSTRACT

Disclosed are electroplating cups for holding, sealing, and providing electrical power to wafers during electroplating, where the electroplating cup can include a cup bottom, an elastomeric lipseal, and an electrical contact element. The cup bottom can include a radially inwardly protruding surface with a plurality of through-holes. The elastomeric lipseal can directly adhere to the radially inwardly protruding surface of the cup bottom, fill the plurality of through-holes, and encircle an inner edge of the cup bottom. In some implementations, this can mitigate the effects of wafer sticking. In some implementations, the cup bottom may be treated to promote adhesion between the elastomeric lipseal and the radially inwardly protruding surface of the cup bottom.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 14/936,328, filed on Nov. 9, 2015, titled“INTEGRATED ELASTOMERIC LIPSEAL AND CUP BOTTOM FOR REDUCING WAFERSTICKING,” which claims the benefit of U.S. Provisional PatentApplication No. 62/190,361, filed Jul. 9, 2015, and titled “CAPTURED CUPLIPSEAL FOR REDUCING WAFER STICKING,” which is incorporated by referenceherein in its entirety and for all purposes.

TECHNICAL FIELD

This disclosure relates to the formation of damascene interconnects forintegrated circuits, and electroplating apparatuses which are usedduring integrated circuit fabrication.

BACKGROUND

Electroplating is a common technique used in integrated circuit (IC)fabrication to deposit one or more layers of conductive metal. In somefabrication processes it is used to deposit one or more levels of copperinterconnects between various substrate features. An apparatus forelectroplating typically includes an electroplating cell having achamber for containing an electrolyte (sometimes called a plating bath)and a substrate holder designed to hold a semiconductor substrate duringelectroplating. In some designs, the wafer holder has a “clamshell”structure in which the substrate perimeter rests against a structurecalled a “cup.”

During operation of the electroplating apparatus, a semiconductorsubstrate is submerged into the plating bath such that at least aplating surface of the substrate is exposed to electrolyte. One or moreelectrical contacts established with the substrate surface are employedto drive an electrical current through the electroplating cell anddeposit metal onto the substrate surface from metal ions available inthe electrolyte. Typically, the electrical contact elements are used toform an electrical connection between the substrate and a bus bar actingas a current source.

An issue arising in electroplating is the potentially corrosiveproperties of the electroplating solution. Therefore, in manyelectroplating apparatus a lipseal is used at the interface of theclamshell and substrate for the purpose of preventing leakage ofelectrolyte and its contact with elements of the electroplatingapparatus other than the inside of the electroplating cell and the sideof the substrate designated for electroplating.

SUMMARY

This disclosure pertains to a cup assembly for holding, sealing, andproviding electrical power to a wafer during electroplating. The cupassembly includes a cup bottom sized to hold the wafer and comprising amain body portion and a radially inwardly protruding surface, where theradially inwardly protruding surface includes a plurality ofthrough-holes. The cup assembly also includes an elastomeric lipsealdisposed on the radially inwardly protruding surface, where theelastomeric lipseal, when pressed against by the wafer, seals againstthe wafer so as to define a peripheral region of the wafer from whichplating solution is substantially excluded during electroplating, whereportions of the elastomeric lipseal pass through the plurality ofthrough-holes. The cup assembly further includes an electrical contactelement disposed on or proximate the elastomeric lipseal, where theelectrical contact element contacts the wafer in the peripheral regionwhen the elastomeric seal seals against the wafer so that the electricalcontact element may provide electrical power to the wafer duringelectroplating.

In some implementations, the portions of the elastomeric lipseal passingthrough the plurality of the through-holes also extend around an inneredge of the cup bottom. In some implementations, the elastomeric lipsealdirectly adheres to the radially inwardly protruding surface, and theportions of the elastomeric seal passing through the plurality ofthrough-holes fill the plurality of through-holes and encircle the inneredge of the cup bottom. In some implementations, the cup assemblyfurther includes an adhesive between the elastomeric lipseal and theradially inwardly protruding surface. In some implementations, theelastomeric lipseal is molded around a portion of the radially inwardlyprotruding surface of the cup bottom.

This disclosure also pertains to a method of preparing a cup assemblyfor holding, sealing, and providing electrical power to a wafer duringelectroplating. The method includes providing a cup bottom sized to holdthe wafer and including a main body portion and a radially inwardlyprotruding surface, where the radially inwardly protruding surfacecomprises a plurality of through-holes. The method further includesaffixing an elastomeric lipseal on the radially inwardly protrudingsurface, where the elastomeric lipseal, when pressed against by thewafer, seals against the wafer so as to define a peripheral region ofthe wafer from which plating solution is substantially excluded duringelectroplating, where portions of the elastomeric lipseal pass throughthe plurality of through-holes.

In some implementations, affixing the elastomeric lipseal includesproviding a mold in the shape of the elastomeric lipseal around aportion of the radially inwardly protruding surface of the cup bottom,including the plurality of through-holes, delivering a lipseal precursorto the mold, and converting the lipseal precursor to the elastomericlipseal. In some implementations, the portions of the elastomericlipseal passing through the plurality of through-holes also extendaround an inner edge of the cup bottom. In some implementations, themethod further includes treating the radially inwardly protrudingsurface of the cup bottom, prior to affixing the elastomeric lipseal,with an agent that facilitates adhesion between the elastomeric lipsealand the radially inwardly protruding surface of the cup bottom. In someimplementations, the method further includes applying an adhesive, priorto affixing the elastomeric lipseal, to the radially inwardly protrudingsurface of the cup bottom or the elastomeric lipseal to promote adhesionbetween the radially inwardly protruding surface of the cup bottom andthe elastomeric lip seal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a wafer holding and positioningapparatus for electrochemically treating semiconductor wafers.

FIG. 1B presents a cross-sectional schematic of an electroplatingsubstrate holder.

FIG. 2 is a cross-sectional schematic of a clamshell assembly havingcontact rings made with multiple flexible fingers.

FIG. 3 is a flowchart illustrating a method of electroplating asemiconductor substrate.

FIG. 4A is a cross-sectional schematic depicting removal of a wafer froman elastomeric lipseal on a cup bottom.

FIG. 4B is a cross-sectional schematic depicting a wafer sticking to anelastomeric lipseal during removal.

FIG. 5A shows a perspective view of an electroplating cup assembly.

FIG. 5B shows a cross-sectional view of the electroplating cup assemblyalong line 5B-5B in FIG. 5A.

FIG. 6A shows a perspective view of an electroplating cup assembly withan interlocked elastomeric lipseal and cup bottom.

FIG. 6B shows a cross-sectional view of the electroplating cup assemblywith the interlocked elastomeric lipseal and cup bottom along line 6B-6Bin FIG. 6A.

FIG. 7A shows a cross-sectional side view of an electroplating cupassembly with an interlocked elastomeric lipseal and cup bottom.

FIG. 7B shows a magnified view of the electroplating cup assembly withthe interlocked elastomeric lipseal and cup bottom of FIG. 7A.

FIG. 8A shows a top perspective view of a portion of an electroplatingcup assembly including a radially inwardly protruding surface of a cupbottom with a plurality of through-holes prior to affixing anelastomeric lipseal.

FIG. 8B shows a cross-sectional view of the electroplating cup assemblyincluding the radially inwardly protruding surface of the cup bottomwith the plurality of through-holes along line 8B-8B of FIG. 8A.

FIG. 9A shows a perspective view of an electroplating cup assembly withan elastomeric lipseal.

FIG. 9B shows a top perspective view of a portion of the electroplatingcup assembly of FIG. 9A and including the elastomeric lipseal on aradially inwardly protruding surface of a cup bottom.

FIG. 9C shows a cross-sectional schematic view of the electroplating cupassembly including the elastomeric lipseal on the radially inwardlyprotruding surface of the cup bottom along line 9C-9C of FIG. 9B.

FIG. 9D shows a magnified view of FIG. 9C of the elastomeric lipsealpassing through a through-hole of the radially inwardly protrudingsurface of the cup bottom.

FIG. 9E shows a bottom perspective view of a portion the electroplatingcup assembly of FIG. 9A and including the elastomeric lipseal on theradially inwardly protruding surface of the cup bottom.

FIG. 10 is a flowchart illustrating a method of forming an elastomericlipseal on a radially inwardly protruding surface of a cup bottom.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the presented concepts. Thepresented concepts may be practiced without some or all of thesespecific details. In other instances, well known process operations havenot been described in detail so as to not unnecessarily obscure thedescribed concepts. While some concepts will be described in conjunctionwith specific embodiments, it will be understood that these embodimentsare not intended to be limiting.

In this disclosure, the terms “semiconductor wafer,” “wafer,”“substrate,” “semiconductor substrate”, “wafer substrate,” “work piece”and “partially fabricated integrated circuit” are used interchangeably.One of ordinary skill in the art would understand that the term“partially fabricated integrated circuit” can refer to a silicon waferduring any of many stages of integrated circuit fabrication thereon.Further, the terms “electrolyte,” “plating bath,” “bath,” and “platingsolution” are used interchangeably. These terms may generally refer tocatholyte (electrolyte present in a cathode chamber or cathode chamberrecirculation loop), or to anolyte (electrolyte present in an anodechamber or anode chamber recirculation loop). The following detaileddescription assumes the disclosure is implemented on a wafer. However,the disclosure is not so limited. The wafer may be of various shapes,sizes, and materials. In addition to semiconductor wafers, other workpieces that may take advantage of this disclosure include variousarticles such as printed circuit boards and the like.

Lipseal and Cup Bottom Design

The information in this section and the following section presents oneexample of an apparatus including a substrate holder that mayincorporate an integrated lipseal as described in more detail in latersections.

A substrate/wafer holding and positioning component of an electroplatingapparatus is presented in FIG. 1A in order to provide some context forthe various integrated lipseal and cup assemblies disclosed herein.Specifically, FIG. 1A presents a perspective view of a wafer holding andpositioning apparatus 100 for electrochemically treating semiconductorwafers. The apparatus 100 includes wafer-engaging components, which aresometimes referred to as “clamshell components,” or a “clamshellassembly,” or just as a “clamshell.” The clamshell assembly comprises acup 101 and a cone 103. As will be shown in subsequent figures, the cup101 holds a wafer and the cone 103 clamps the wafer securely in the cup.During an electroplating process, the semiconductor wafer is supportedby the cup 101 and the cone 103. Other cup and cone designs beyond thosespecifically depicted here can be used. A common feature is that a cupthat has an interior region in which the wafer resides and that the conepresses the wafer against the cup to hold it in place.

In the depicted embodiment, the clamshell assembly (which includes thecup 101 and the cone 103) is supported by struts 104, which areconnected to a top plate 105. This assembly (101, 103, 104, and 105) isdriven by a motor 107 via a spindle 106 connected to the top plate 105.The motor 107 is attached to a mounting bracket (not shown). The spindle106 transmits torque (from the motor 107) to the clamshell assemblycausing rotation of a wafer (not shown in this figure) held thereinduring plating. An air cylinder (not shown) within the spindle 106 alsoprovides a vertical force for engaging the cup 101 with the cone 103.When the clamshell is disengaged (not shown), a robot with an endeffector arm can insert a wafer in between the cup 101 and the cone 103.After a wafer is inserted, the cone 103 is engaged with the cup 101,which immobilizes the wafer within apparatus 100 leaving a workingsurface on one side of the wafer (but not the other) exposed for contactwith the electrolyte solution.

In certain embodiments, the clamshell assembly includes a spray skirt109 that protects the cone 103 from splashing electrolyte. In thedepicted embodiment, the spray skirt 109 includes a verticalcircumferential sleeve and a circular cap portion. A spacing member 110maintains separation between the spray skirt 109 and the cone 103.

For the purposes of this discussion, the assembly including components101-110 is collectively referred to as a “wafer holder” (or “substrateholder”) 111. Note however, that the concept of a “waferholder”/“substrate holder” extends generally to various combinations andsub-combinations of components that engage a wafer/substrate and allowits movement and positioning.

A tilting assembly (not shown) may be connected to the wafer holder topermit angled immersion (as opposed to flat horizontal immersion) of thewafer into a plating solution. A drive mechanism and arrangement ofplates and pivot joints are used in some embodiments to move wafer theholder 111 along an arced path (not shown) and, as a result, tilt theproximal end of wafer holder 111 (which includes the cup and coneassembly) while it is immersed into the plating solution.

Further, the entire wafer holder 111 is lifted vertically either up ordown to immerse the end of wafer holder into a plating solution via anactuator (not shown). Thus, a two-component positioning mechanismprovides both vertical movement along a trajectory perpendicular to anelectrolyte surface and a tilting movement allowing deviation from ahorizontal orientation (i.e., parallel to the electrolyte surface) forthe wafer (angled-wafer immersion capability).

Note that the wafer holder 111 is used with a plating cell 115 having aplating chamber 117 which houses an anode chamber 157 and a platingsolution. The anode chamber 157 holds an anode 119 (e.g., a copperanode) and may include membranes or other separators designed tomaintain different electrolyte chemistries in the anode compartment anda cathode compartment. In the depicted embodiment, a diffuser 153 isemployed for directing electrolyte upward toward the rotating wafer in auniform front. In certain embodiments, the flow diffuser is a highresistance virtual anode (HRVA) plate, which is made of a solid piece ofinsulating material (e.g. plastic), having a large number (e.g.4,000-15,000) of one dimensional small holes (0.01 to 0.050 inches indiameter) and connected to the cathode chamber above the plate. Thetotal cross-section area of the holes is less than about 5 percent ofthe total projected area, and, therefore, introduces substantial flowresistance in the plating cell helping to improve the plating uniformityof the system. Additional description of a high resistance virtual anodeplate and a corresponding apparatus for electrochemically treatingsemiconductor wafers is provided in U.S. Pat. No. 8,308,931, issued onNov. 13, 2012, which is hereby incorporated by reference herein in itsentirety. The plating cell may also include a separate membrane forcontrolling and creating separate electrolyte flow patterns. In anotherembodiment, a membrane is employed to define an anode chamber, whichcontains electrolyte that is substantially free of suppressors,accelerators, or other organic plating additives.

The plating cell 115 may also include plumbing or plumbing contacts forcirculating electrolyte through the plating cell—and against the workpiece being plated. For example, the plating cell 115 includes anelectrolyte inlet tube 131 that extends vertically into the center ofanode chamber 157 through a hole in the center of anode 119. In otherembodiments, the cell includes an electrolyte inlet manifold thatintroduces fluid into the cathode chamber below the diffuser/HRVA plateat the peripheral wall of the chamber (not shown). In some cases, theinlet tube 131 includes outlet nozzles on both sides (the anode side andthe cathode side) of the membrane 153. This arrangement deliverselectrolyte to both the anode chamber and the cathode chamber. In otherembodiments, the anode and cathode chamber are separated by a flowresistant membrane 153, and each chamber has a separate flow cycle ofseparated electrolyte. As shown in the embodiment of FIG. 1A, an inletnozzle 155 provides electrolyte to the anode-side of membrane 153.

In addition, plating cell 115 includes a rinse drain line 159 and aplating solution return line 161, each connected directly to the platingchamber 117. Also, a rinse nozzle 163 delivers deionized rinse water toclean the wafer and/or cup during normal operation. Plating solutionnormally fills much of the chamber 117. To mitigate splashing andgeneration of bubbles, the chamber 117 includes an inner weir 165 forplating solution return and an outer weir 167 for rinse water return. Inthe depicted embodiment, these weirs are circumferential vertical slotsin the wall of the plating chamber 117.

FIG. 1B provides a more detailed cross-sectional view of the substrateholding component 100A (the cup/cone assembly or clamshell assembly) ofthe electroplating apparatus, including a cross-sectional view of cup101 and cone 103. Note that the cup/cone assembly 100A depicted in FIG.1B is not intended to be proportionately accurate. Cup 101, having cupbottom 102, supports the lipseal 143, the contacts 144, bus bar, andother elements, and is itself supported by top plate 105 via struts 104.Generally, a substrate 145 rests on the lipseal 143, just above thecontact 144, which is configured to support it. Cup 101 also includes anopening (as labeled in the figure) through which an electroplating bathsolution may contact the substrate 145. Note that electroplating takesplace on the front side 142 of substrate 145. Thus, the periphery ofsubstrate 145 rests on a bottom inward protrusion of the cup 101 (e.g.,“knife-shaped” edge) referred to as the cup bottom 102, or morespecifically on lipseal 143 which is positioned on the radially inwardedge of the cup bottom 102.

Cone 103 presses down on the back side of substrate 145 to engage it andhold it in place and to seal it against lipseal 143 during submersion ofthe substrate into the electroplating bath during electroplating. Thevertical force from cone 103, which is transferred through substrate 145compresses lipseal 143 to form the fluid tight seal. Lipseal 143prevents electrolyte from contacting the backside of substrate 145(where it could introduce contaminating metal atoms directly intosilicon) and from reaching sensitive components of apparatus 100, suchas contact fingers that establish electrical connections to edgeportions of substrate 145. This electrical connection and associatedelectrical contacts 144, themselves sealed and protected by the lipsealfrom becoming wet, is used to supply current to conductive portions ofsubstrate 145 that are exposed to the electrolyte. Overall, lipseal 143separates unexposed edge portions of substrate 145 from exposed portionsof substrate 145. Both portions include conductive surfaces that are inelectronic communication with each other.

To load a substrate 145 into cup/cone assembly 100A, cone 103 is liftedfrom its depicted position via spindle 106 until there is a sufficientgap between the cup 101 and the cone 103 to allow insertion of substrate145 into the cup/cone assembly 100A. The substrate 145 is then inserted,in some embodiments by a robot arm, and allowed to rest lightly on thelipseal and cup bottom 102 (or on a related component attached to thecup, such as a lipseal 143 as described below). In some embodiments, thecone 103 is lifted from its depicted position until it touches top plate105. Subsequently, the cone 103 is then lowered to press and engage thesubstrate against the periphery of cup 101 (the cup bottom 102) orattached lipseal 143 as depicted in FIG. 1B. In some embodiments, thespindle 106 transmits both a vertical force for causing the cone 103 toengage the substrate 145, and also the torque for rotating the cup/coneassembly 100A as well as the substrate 145 being held by the cup/coneassembly. FIG. 1B indicates the directionality of the vertical force androtational orientation of the torque by solid arrows 150 and dashedarrows 152, respectively. In some embodiments, electroplating of thesubstrate 145 typically occurs while the substrate 145 is rotating. Incertain such embodiments, rotating the substrate 145 duringelectroplating aids in achieving uniform plating, and aids in removingmetallic buildup removal as part of the process described in detailhereafter.

In some embodiments, there may also be an additional seal 149 locatedbetween the cup 101 and the cone 103, which engages the surfaces of thecup 101 and cone 103 to generally form a substantially fluid-tight sealwhen the cone 103 engages the substrate 145. The additional sealingprovided by cup/cone seal 149 functions to further protect the backsideof the substrate 145. Cup/cone seal 149 may be affixed to either the cup101, or to the cone 103, engaging the alternative element when the cone103 engages the substrate 145. Cup/cone seal 149 may be a singlecomponent seal or a multi-component seal. Similarly, lipseal 143 may bea single component seal or a multi-component seal. Furthermore, avariety of materials may be used to construct seals 143 and 149, aswould be appreciated by one of ordinary skill in the art. For instance,in some embodiments, the lipseal is constructed of an elastomericmaterial, and in certain such embodiments, a perfluoropolymer.

As stated above, an electroplating clamshell typically includes alipseal and one or more contact elements to provide sealing andelectrical connection functions. A lipseal may be made from anelastomeric material. The lipseal forms a seal with the surface of thesemiconductor substrate and excludes the electrolyte from a peripheralregion of the substrate. No deposition occurs in this peripheral regionand it is not used for forming IC devices, i.e., the peripheral regionis not a part of the working surface. Sometimes, this region is alsoreferred to as an edge exclusion area because the electrolyte isexcluded from the area. The peripheral region is used for supporting andsealing the substrate during processing, as well as for makingelectrical connection with the contact elements. Since it is generallydesirable to increase the working surface, the peripheral region needsto be as small as possible while maintaining the functions describedabove. In certain embodiments, the peripheral region is between about0.5 millimeters and 3 millimeters from the edge of the substrate.

During installation, the lipseal and contact elements are assembledtogether with other components of the clamshell. One having ordinaryskilled in the art can appreciate the difficultly of this operation,particularly, when the peripheral region is small. An overall openingprovided by this clamshell is comparable to the size of the substrate(e.g., an opening for accommodating 200 mm wafers, 300 mm wafers, 450 mmwafers, etc.). Furthermore, substrates have their own size tolerances(e.g., +/−0.2 millimeters for a typical 300 mm wafer according to theSEMI specification). A particularly difficult task is alignment of theelastomeric lipseal and contact elements, since both are made fromrelatively flexible materials. These two components need to have veryprecise relative location. When a sealing edge of the lipseal andcontact elements are positioned too far away from each other,insufficient or no electrical connection may be formed between thecontacts and substrate during operation of the clamshell. At the sametime, when the sealing edge is positioned too close to the contacts, thecontacts may interfere with the seal and cause leakage into theperipheral region. For example, conventional contact rings are oftenmade with multiple flexible “fingers” that are pressed in a spring-likeaction onto the substrate to establish an electrical connection as shownin the clamshell assembly of FIG. 2 (note cup 201, cone 203, and lipseal212).

Method of Sealing a Substrate in a Clamshell

Also disclosed herein are methods of sealing a semiconductor substratein an electroplating clamshell having an elastomeric lipseal. Theflowchart of FIG. 3 is illustrative of some of these methods. Forinstance, some methods involve opening the clamshell (block 302),providing a substrate to the electroplating clamshell (block 304),lowering the substrate through an upper portion of the lipseal and ontoa sealing protrusion of the lipseal (block 306), and compressing a topsurface of the upper portion of the lipseal to align the substrate(block 308). In some embodiments, compressing the top surface of theupper portion of the elastomeric lipseal during operation 308 causes aninner side surface of the upper portion to contact the semiconductorsubstrate and push on the substrate aligning it in the clamshell.

After aligning the semiconductor substrate during operation 308, in someembodiments, the apparatus presses the semiconductor substrate inoperation 310 to form a seal between the sealing protrusion and thesemiconductor substrate. In certain embodiments, compressing the topsurface continues during pressing on the semiconductor substrate. Forexample, in certain such embodiments, compressing the top surface andpressing on the semiconductor substrate may be performed by twodifferent surfaces of the cone of the clamshell. Thus, a first surfaceof the cone may press on the top surface to compress it, and a secondsurface of the cone may press on the substrate to form a seal with theelastomeric lipseal. In other embodiments, compressing the top surfaceand pressing on the semiconductor substrate are performed independentlyby two different components of the clamshell. These two pressingcomponents of the clamshell are typically independently movable withrespect to one another, thus allowing compression of the top surface tobe halted once the substrate is pressed upon and sealed against thelipseal by the other pressing component. Furthermore, the compressionlevel of the top surface may be adjusted based upon the diameter of thesemiconductor substrate by independently altering the pressing forceexerted upon it by its associated pressing component.

These operations may be part of a larger electroplating process, whichis also depicted in the flowchart of FIG. 3 and briefly described below.

Initially, the lipseal and contact area of the clamshell may be cleanand dry. The clamshell is opened (block 302) and the substrate is loadedinto the clamshell. In certain embodiments, the contact tips sitslightly above the plane of the sealing lip and the substrate issupported, in this case, by the array of contact tips around thesubstrate periphery. The clamshell is then closed and sealed by movingthe cone downward. During this closure operation, the electricalcontacts and seals are established according to various embodimentsdescribed above. Further, the bottom corners of the contacts may beforce down against the elastic lipseal base, which results in additionalforce between the tips and the front side of the wafer. The sealing lipmay be slightly compressed to ensure the seal around the entireperimeter. In some embodiments, when the substrate is initiallypositioned into the cup only the sealing lip is contact with the frontsurface. In this example, the electrical contact between the tips andthe front surface is established during compression of the sealing lip.

Once the seal and the electrical contact are established, the clamshellcarrying the substrate is immersed into the plating bath and is platedin the bath while being held in the clamshell (block 312). A typicalcomposition of a copper plating solution used in this operation includescopper ions at a concentration range of about 0.5-80 g/L, morespecifically at about 5-60 g/L, and even more specifically at about18-55 g/L and sulfuric acid at a concentration of about 0.1-400 g/L.Low-acid copper plating solutions typically contain about 5-10 g/L ofsulfuric acid. Medium and high-acid solutions contain about 50-90 g/Land 150-180 g/L sulfuric acid, respectively. The concentration ofchloride ions may be about 1-100 mg/L. A number of copper platingorganic additives such as Enthone Viaform, Viaform NexT, Viaform Extreme(available from Enthone Corporation in West Haven, Conn.), or otheraccelerators, suppressors, and levelers known to those of skill in theart can be used. Examples of plating operations are described in moredetail in U.S. patent application Ser. No. 11/564,222 filed on Nov. 28,2006, which is hereby incorporated by reference in its entirety herein.Once the plating is completed and an appropriate amount of material hasbeen deposited on the front surface of the substrate, the substrate isthen removed from the plating bath. The substrate and clamshell are thenspun to remove most of the residual electrolyte on the clamshellsurfaces which has remained there due to surface tension and adhesiveforces. The clamshell is then rinsed while continued to be spun todilute and flush as much of the entrained electrolytic fluid as possiblefrom clamshell and substrate surfaces. The substrate is then spun withrinsing liquid turned off for some time, usually at least about 2seconds to remove some remaining rinsate. The process may proceed byopening the clamshell (block 314) and removing the processed substrate(block 316). Operational blocks 304 through 316 may be repeated multipletimes for new wafer substrates, as indicated in FIG. 3.

Electroplating Cup Assemblies with Integrated Elastomeric Lipseal andCup Bottom for Reducing Wafer Sticking

The present disclosure relates with an integrated elastomeric lipsealand cup bottom of an electroplating cup assembly. As used herein,“integrated” can refer to two or more features attached or connected toone another such that neither of the features can be readily detachedfrom one another. Nonetheless, two or more features that are integratedcan be made of different materials and can serve independently differentfunctions.

Typically, a cup-and-cone electroplating clamshell includes anelastomeric lipseal, which is manufactured separately from the othercomponents of the electroplating clamshell. In other words, theelastomeric lipseal is manufactured as a distinct component forsubsequent incorporation into the electroplating clamshell whenassembled for operational use. This can stem from the fact that otherclamshell components are generally not composed of elastomeric material.Rather, such clamshell components can be made of rigid materialsincluding metals or hard plastics, so typically a separate molding orfabrication process would be used for them. However, because the lipsealis made of a flexible elastomeric material, and because the lipseal isthin and can be delicate in shape, the lipseal may separate from the cupbottom when a wafer is lifted away or otherwise removed from a cupbottom after electroplating.

FIG. 4A is a cross-sectional schematic depicting removal of a wafer froman elastomeric lipseal on a cup bottom. FIG. 4B is a cross-sectionalschematic depicting a wafer sticking to an elastomeric lipseal duringremoval. FIG. 4A depicts normal removal of an electroplated wafer fromthe elastomeric lipseal while FIG. 4B depicts removal in which theelastomeric lipseal sticks to the wafer and pulls away from the cupbottom. In wafer level packaging applications, a photoresist layer canbe used on the wafer to mask areas where plating is not desirable. Thephotoresist can extend to within 2-4 mm of the wafer edge and can bepresent in the interface between the elastomeric lipseal and the wafer.Over time, photoresist residue can build up on the elastomeric lipseal,causing the wafer to stick to it. In addition, residual components fromthe electroplating bath may also form a residue on the elastomericlipseal, which can further contribute to wafer sticking. Other sourcesof residue may also be present depending on the particular applications.

In FIGS. 4A and 4B, an elastomeric lipseal 412 is disposed on a cupbottom 401 of an electroplating cup assembly. An electrical contactelement 408 is disposed on the elastomeric lipseal 412 and is configuredto provide electrical power to a wafer 413 when in contact with thewafer 413. Prior to removal, the elastomeric lipseal 412 may support,align, and seal the wafer 413 from electrolyte in the electroplating cupassembly. As shown in FIG. 4A, when adhesion between the wafer 413 andthe elastomeric lipseal 412 is minimal, the wafer 413 can be readilyremoved without damage to any components of the electroplating cupassembly. However, as shown in FIG. 4B, when adhesion between the wafer413 and the elastomeric lipseal 412 is sufficiently strong, the wafer413 sticks to the elastomeric lipseal 412. Tools for removing the wafer413, such as a vacuum end effector of a wafer handling robot, may breakcontact and fail to remove the wafer 413 from the electroplating cupassembly. Moreover, the elastomeric lipseal 413 may pull away from thecup bottom 401, which can damage the electroplating cup assembly or atleast necessitate replacement.

FIG. 5A shows a perspective view of an electroplating cup assembly. Asshown in FIG. 5A, an electroplating cup assembly 500 includes severalfeatures. The electroplating cup assembly 500 includes a cup bottom 501that can be ring-shaped to define an opening 525 to allow exposure of awafer to a plating solution. However, it will be understood that the cupbottom 501 can have other geometries other than ring-shaped. Theelectroplating cup assembly 500 can further include a bus ring 502surrounding a main body portion of the cup bottom 501 and radiallyinwardly facing towards a center of the opening 525. In someimplementations, the bus ring 502 may be a continuous thick ring ofmetal. A plurality of struts 504 may extend from a top surface of thebus ring 502 to support the electroplating cup assembly 500 in aclamshell. The electroplating cup assembly 500 can further include anelastomeric lipseal 512 positioned in the electroplating cup assembly500 to prevent plating solution from reaching a peripheral region of thewafer. The elastomeric lipseal 512 can be disposed along a radiallyinwardly protruding surface of the cup bottom 501 and radially inwardlyextending towards the center of the opening 525.

FIG. 5B shows a cross-sectional view of the electroplating cup assemblyalong line 5B-5B in FIG. 5A. As shown in FIG. 5B, the cup bottom 501 caninclude a main body portion that the bus ring 502 is disposed on. Thecup bottom 501 also includes a portion that radially inwardly protrudestowards the center of the opening 525 defined by the cup bottom 501. Aradially inwardly protruding portion can refer to a structure protrudingtowards a center of a shape, including a shape defined by the cup bottom501. The radially inwardly protruding portion of the cup bottom 501 andthe main body portion of the cup bottom 501 can be connected by anattaching mechanism 505, such as a screw. The radially inwardlyprotruding portion of the cup bottom 501 provides an exposed surface inthe opening upon which additional features of the electroplating cupassembly 500 may be built. This surface may be referred to as a radiallyinwardly protruding surface 503. The elastomeric lipseal 512 can bedisposed on the radially inwardly protruding surface 503 of the cupbottom 501. The elastomeric lipseal 512 can support a wafer 513 providedin the electroplating cup assembly 500. The elastomeric lipseal 512 canalso align and seal the wafer 513 in the electroplating cup assembly 500to substantially exclude plating solution from reaching a peripheralregion of the wafer 513. The electroplating cup assembly 500 can furtherinclude one or more electrical contact elements 508 configured toprovide an electrical connection between an external power supply andthe wafer 513. The one or more electrical contact elements 508 can bedisposed on or proximate the elastomeric lipseal 512. The one or moreelectrical contact elements 508 may contact the wafer 513 in theperipheral region when the elastomeric lipseal 512 seals against thewafer 513. The one or more electrical contact elements 508 may beconfigured to provide electrical power to the wafer 513 duringelectroplating. In some implementations, the one or more electricalcontact elements 508 may be electrically connected to a currentdistribution bus 516 for supplying current to the one or more electricalcontact elements 508, which may be electrically connected to the busring 502. In some implementations, the one or more electrical contactelements 508 may be integrated with the elastomeric lipseal 512, asdescribed in U.S. application Ser. No. 14/685,526 (attorney docket no.LAMRP162), filed Apr. 13, 2015, and titled “LIPSEALS AND CONTACTELEMENTS FOR SEMICONDUCTOR ELECTROPLATING APPARATUSES,” and U.S. patentapplication Ser. No. 13/584,343 (attorney docket no. NOVLP433), filedAug. 13, 2012, and titled “LIPSEALS AND CONTACT ELEMENTS FORSEMICONDUCTOR ELECTROPLATING APPARATUSES,” each of which is incorporatedherein by reference in its entirety and for all purposes.

As described earlier, the elastomeric lipseal 512 on the radiallyinwardly protruding surface 503 of the cup bottom 501 in FIG. 5B may bevulnerable to wafer sticking. The present disclosure can mitigate theeffects of wafer sticking by manufacturing the elastomeric lipseal withthe cup bottom of a cup assembly. That way, the elastomeric lipseal andthe cup bottom can be integrated in a manner that makes it difficult forthem to separate from one another during electroplating operations, andmore particularly during removal of the wafer from the cup assembly. Theelastomeric lipseal and the cup bottom can be strongly attached and/oradhered to each other so that they resist separation. As describedbelow, the elastomeric lipseal can be disposed, formed, placed, orpositioned directly on the cup bottom and directly into one or morethrough-holes of the cup bottom. Such an arrangement can improveadhesion of the elastomeric lipseal to the cup bottom.

FIG. 6A shows a perspective view of an electroplating cup assembly withan interlocked elastomeric lipseal and cup bottom. The electroplatingcup 600 includes a cup bottom 601 that can be ring-shaped to define anopening 625 to allow exposure of a wafer to a plating solution. However,it will be understood that the cup bottom 601 can have geometries otherthan ring-shaped. The electroplating cup assembly 600 can furtherinclude a bus ring 602 surrounding a main body portion of the cup bottom601 and radially inwardly facing towards a center of the opening 625. Insome implementations, the bus ring 602 may be a continuous thick ring ofmetal. A plurality of struts 604 may extend from a top surface of thebus ring 602 to support the electroplating cup assembly 600 in aclamshell. The electroplating cup assembly 600 can further include anelastomeric lipseal 612 positioned in the electroplating cup assembly600 to prevent plating solution from reaching a peripheral region of thewafer. The elastomeric lipseal 612 can be disposed along a radiallyinwardly protruding surface of the cup bottom 601 and radially inwardlyextending towards the center of the opening 625.

FIG. 6B shows a cross-sectional view of the electroplating cup assemblywith the interlocked elastomeric lipseal and cup bottom along line 6B-6Bin FIG. 6A. As shown in FIG. 6B, the cup bottom 601 can include a mainbody portion upon which the bus ring 602 is disposed on. The cup bottom601 can also include a portion that radially inwardly protrudes towardsthe center of the opening defined by the cup bottom 601. The radiallyinwardly protruding portion of the cup bottom 601 and the main bodyportion can be connected by an attaching mechanism 605, such as a screw.The radially inwardly protruding portion of the cup bottom 601 providesan exposed surface in the opening upon which additional features of theelectroplating cup assembly 600 may be built. This surface may bereferred to as a radially inwardly protruding surface 603. Theelastomeric lipseal 612 can be disposed on the radially inwardlyprotruding surface 603 of the cup bottom 601.

In FIG. 6B, the radially inwardly protruding surface 603 can be shapedand structured to improve adhesion of the elastomeric lipseal 612 to thecup bottom 601. In some implementations, the radially inwardlyprotruding surface 603 can include a mechanical structure for preventingthe elastomeric lipseal 612 from detaching from the surface of the cupbottom 601 to which it is attached. For example, the mechanicalstructure can include one or more holes (typically a series of holes) ina radially inwardly protruding surface 603 of the cup bottom 601. Eachof the holes can hold a “pillar” of elastomeric lipseal material so thatthe elastomeric lipseal 612 can encircle the inner lip of the cup bottom601 where the holes exist, as shown in FIG. 6B. In some implementations,the radially inwardly protruding surface 603 can be outfitted withstructural features other than holes. Such structural features caninclude pegs, divots, serrations, hooks, trenches, and the like. Theelastomeric lipseal 612 can be disposed on and even surrounding thestructural features so that the elastomeric lipseal 612 can bemechanically interlocked or integrated with the cup bottom 601.

In some implementations, the cup bottom 601 may be made from arelatively rigid material, or at least a more rigid material than theelastomeric lipseal 612. For example, the cup bottom can be made ofpoly(p-phenylene sulfide) (PPS). Adhesion to PPS and similar cup bottommaterials can be difficult, so retention may be achieved with one ormore of the following: a chemical pretreatment of the cup bottom 601, insitu molding of the elastomeric lipseal 612 in the cup bottom 601, andmechanical interlocking of the elastomeric lipseal 612 with the cupbottom 601. This can improve adhesion of the elastomeric lipseal 612 tothe cup bottom 601, which can prevent the elastomeric lipseal 612 fromseparating and reduce the effects of wafer sticking.

The elastomeric lipseal 612 can support a wafer 613 in theelectroplating cup assembly 600. The elastomeric lipseal 612 can alsoalign and seal the wafer 613 in the electroplating cup assembly 600 tosubstantially exclude the plating solution from reaching a peripheralregion of the wafer 613. The radially inwardly protruding surface 603 ofthe cup bottom 601 (and the associated elastomeric lipseal 612) can besized and shaped to engage with a perimeter of the wafer 613. In variousimplementations, the wafer 613 is a semiconductor wafer such as a200-mm, 300-mm, or 450-mm wafer, so the inner diameter of theelastomeric lipseal 612, and typically the supporting cup bottom 601, isvery slightly smaller than 200-mm, 300-mm, or 450-mm, such as about 1-5mm smaller.

The electroplating cup assembly 600 can further include one or moreelectrical contact elements 608 configured to provide an electricalconnection between an external power supply and the wafer 613. The oneor more electrical contact elements 608 can be disposed on or proximatethe elastomeric lipseal 612. The one or more electrical contact elements608 may contact the wafer 613 in the peripheral region when theelastomeric lipseal 612 seals against the wafer 613. The one or moreelectrical contact elements 608 may be configured to provide electricalpower to the wafer 613 during electroplating. In some implementations,the one or more electrical contact elements 608 may be electricallyconnected to a current distribution bus for supplying current to the oneor more electrical contact elements 608, which may be electricallyconnected to the bus ring 602. In some implementations, the one or moreelectrical contact elements 608 may be integrated with the elastomericlipseal 612.

FIG. 7A shows a cross-sectional side view of an electroplating cupassembly with an interlocked elastomeric lipseal and cup bottom. FIG. 7Bshows a magnified view of the electroplating cup assembly with theinterlocked elastomeric lipseal and cup bottom of FIG. 7A. Anelectroplating cup assembly 700 can include a ring-shaped cup bottom701, where the ring-shaped cup bottom 701 includes a main body portion711 and a moment arm 703. The moment arm 703 can be a relatively thinextension (radially-inward) of the main body of the ring-shaped cupbottom 701, which serves to support the elastomeric lipseal 712. A busring 702 disposed over the main body portion 711 of the ring-shaped cupbottom 701. A wafer 703 may be supported in the electroplating cupassembly 700 by one or more features of the ring-shaped cup bottom 701.One or more electrical contact elements 708 can be disposed on or overthe elastomeric lipseal 712, where the one or more electrical contactelements 708 can contact the wafer 713. The moment arm 703 may flex to acertain degree in response to pressure exerted by a cone when the wafer713 is pressed against by the cone into its sealing and electricalcontact arrangement. In contrast, the main body portion 711 is designedto be relatively thick such that it does not substantially flex when thewafer is pressed against the moment arm 703.

The elastomeric lipseal 712 can be mechanically interlocked with themoment arm 703. The moment arm 703 can include one or morethrough-holes. In FIG. 7B, the elastomeric lipseal 712 can pass throughone or more through-holes to form a pillar of elastomeric lipsealmaterial in the one or more through-holes. In some implementations,portions of the elastomeric lipseal 712 pass through the through-holesand extend around an inner lip or an inner edge of the cup bottom 701.In some implementations, a portion of the elastomeric lipseal 712 overthe inner lip or the inner edge of the cup bottom 701 may protrude tocontact the wafer 713. In some implementations, the elastomeric lipseal712 may be molded to the moment arm 703 of the cup bottom 701 and aroundthe inner edge of the cup bottom 701. This can inhibit the uncoupling ofthe elastomeric lipseal 712 from the cup bottom 701.

FIG. 8A shows a top perspective view of a portion of an electroplatingcup assembly including a radially inwardly protruding surface of a cupbottom with a plurality of through-holes prior to affixing anelastomeric lipseal. An electroplating cup assembly 800 includes a cupbottom 801 with a radially inwardly protruding surface 803. The radiallyinwardly protruding surface 803 includes a plurality of through-holes818. The plurality of through-holes 818 can provide a structural featureby which elastomeric lipseal material can form into and around tomechanically interlock the elastomeric lipseal material to the cupbottom 801.

The total number of through-holes 818 in the radially inwardlyprotruding surface 803 of the cup bottom 801 may be between about 100and about 500, or between about 150 and about 300, or between about 180and about 250. The diameter of the through-holes 818 in the radiallyinwardly protruding surface 803 of the cup bottom may be between about0.01 inches and about 0.05 inches, or between about 0.02 inches andabout 0.04 inches. The distance between the inner edge of the cup bottom801 and the center of the through-holes 818 may be between about 0.005and about 0.05 inches, or between about 0.01 and about 0.03 inches. Inthe angular/azimuthal direction, the plurality of through-holes 818 maybe uniformly spaced apart. The separation distance between centers ofadjacent through-holes 818 in the angular/azimuthal direction in theradially inwardly protruding surface 803 may be between about 0.05 andabout 0.25 inches, or between about 0.08 and about 0.18 inches. As anexample, the radially inwardly protruding surface 803 can have 240through-holes 818, each of which are 0.026 inches in diameter, with anazimuthal separation of 0.15 inches between hole-centers. In someimplementations, the through-holes 818 are located directly under asealing feature of the elastomeric lipseal in the cup bottom 801.

FIG. 8B shows a cross-sectional view of the electroplating cup assemblyincluding the radially inwardly protruding surface of the cup bottomwith the plurality of through-holes along line 8B-8B of FIG. 8A. The cupbottom 801 includes a main body portion 811 and a radially inwardlyprotruding surface 803 with a through-hole 818 extending through theradially inwardly protruding surface 803. The through-hole 818 isdefined between an inner edge 804 of the cup bottom 801 and a remainderof the radially inwardly protruding surface 803 of the cup bottom 801.The thickness of the cup bottom 701 at the location of the through-hole818 may be between about 0.01 and about 0.05 inches, or between about0.02 and about 0.04 inches.

The material from which the cup bottom 801 is formed is typically arelatively rigid material, which may be conductive or insulating. Insome implementations, the cup bottom 801 is made from a metal such astitanium, or a titanium alloy, or stainless steel. In implementationswhere the cup bottom 801 is made from a conductive material, theconductive material may be coated with an insulating material. In someimplementations, the cup bottom 801 is made from a non-conductivematerial such as a plastic, including but not limited to PPS orpolyether ether ketone (PEEK). In some implementations, thenon-conductive material is a polymeric material that is unfilled. Insome implementations, the cup bottom 801 is made from a ceramicmaterial. In certain implementations, the cup bottom 801 has a rigiditycharacterized by a Young's modulus of between about 300,000 and55,000,000 psi, or more particularly between about 450,000 and30,000,000 psi.

Prior to affixing an elastomeric lipseal to the cup bottom 801, adhesionto the radially inwardly protruding surface 803 can be facilitated bytreating the radially inwardly protruding surface 803. In someimplementations, at least the radially inwardly protruding surface 803of the cup bottom 801 is exposed to an agent that improves adhesionbetween the elastomeric lipseal and radially inwardly protrudingsurface. This treatment may chemically or physically change the surfaceof the cup bottom 801 exposed to the agent by, for example, increasingroughness, applying or removing electrical charge, oxidizing or reducingchemical moieties, and/or passivating reactive moieties. The treatmentprepares the surface of the cup bottom 801 to accept an adhesive orotherwise improve the bond between the elastomeric lipseal and the cupbottom 801. In some implementations, the treatment improves adhesion byoxidizing the surface of the cup bottom 801. Where the cup bottom 801 ismade from PPS or a similar polymeric material, the treatment may oxidizethe surface of the polymeric material prior to applying an adhesionpromoter. A treatment agent can include a plasma or strong oxidizingacid, such as nitric acid, sulfuric acid, perchloric acid, persulfuricacid, etc. In some implementations, the treatment includes contacting atleast the radially inwardly protruding surface 803 with concentratednitric acid (such as between about 20-70% by weight) for about 1 to 5minutes (such as about 2 minutes). The contact may involve soaking. Insome implementations, thereafter, the method may apply an adhesive orsolvent-based adhesion promoter prior to affixing the elastomericlipseal.

Prior to affixing the elastomeric lipseal to the cup bottom 801,adhesion to the radially inwardly protruding surface 803 can befacilitated by application of an adhesive or adhesion promoter betweenthe elastomeric lipseal and the radially inwardly protruding surface803. This can be done in addition to or in the alternative with thetreatment agent for treating at least the radially inwardly protrudingsurface 803. Various types of adhesives or adhesion promoters may beused to improve adherence of the elastomeric lipseal to the radiallyinwardly protruding surface 803. In some implementations, the methoduses a solvent-based adhesion promoter that enhances surface cleaningand aids in penetration of the elastomeric lipseal into the waferbonding surface. One example of a suitable adhesive is 1200 OS from DowCorning Corporation of Midland, Mich. In some implementations, theadhesive or adhesion promoter is applied after treatment with atreatment agent as described above.

FIG. 9A shows a perspective view of an electroplating cup assembly withan elastomeric lipseal. In the illustrated electroplating cup assembly900, an elastomeric lipseal 912 maybe molded in (or into or onto, etc.)a cup bottom 901 or otherwise affixed to the cup bottom 901. The cupbottom 901 can include a radially inwardly protruding surface 903 uponwhich the elastomeric lipseal 912 is disposed. As shown in FIG. 9A, theelectroplating cup assembly 900 is an annular structure, and the cupbottom 901 and the elastomeric lipseal 912 are generally ring-shaped.

FIG. 9B shows a top perspective view of a portion of the electroplatingcup assembly of FIG. 9A and including the elastomeric lipseal on aradially inwardly protruding surface of a cup bottom. FIG. 9C shows across-sectional schematic view of the electroplating cup assemblyincluding the elastomeric lipseal on the radially inwardly protrudingsurface of the cup bottom along line 9C-9C of FIG. 9B. FIG. 9B shows aradial slice of the annular structure of the electroplating cup assembly900 of FIG. 9A. The cup bottom 901 includes a main body portion 911 anda radially inwardly protruding surface 903. The elastomeric lipseal 912is disposed over a portion of the cup bottom 901 that includes theradially inwardly protruding surface 903, where the radially inwardlyprotruding surface 903 includes a plurality of through-holes. Portions926 of the elastomeric lipseal 912 pass through the through-holes. Theportions 926 of the elastomeric lipseal 912 may also pass around aninner lip 904 of the radially inwardly protruding surface 903. In someimplementations, the portions 926 of the elastomeric lipseal 912 canencircle the inner lip 904 of the radially inwardly protruding surface903 so that the elastomeric lipseal 912 can be mechanically interlockedwith the cup bottom 901. In some implementations, the elastomericlipseal 912 directly adheres to the radially inwardly protruding surface903, and the portions 926 of the elastomeric lipseal 912 passing throughthe plurality of through-holes fill the plurality of through holes. Insome implementations, the portions 926 of the elastomeric lipseal 912can constitute pillars of elastomeric material. The pillars ofelastomeric material 926 can be formed in, into, onto, along, and aroundstructural features of the radially inwardly protruding surface 903 ofthe cup bottom 901, including through-holes of the radially inwardlyprotruding surface 903 of the cup bottom 901.

The cup bottom 901, including the radially inwardly protruding surface903, can be made of a relatively rigid material, such as PPS or PEEK. Insome implementations, the cup bottom 901 can be made of a metal, such astitanium, or a titanium alloy, or stainless steel. The elastomericlipseal 912, including the pillars of elastomeric material 926, can bemade of a material that is less rigid than the cup bottom 901. In someimplementations, the elastomeric lipseal 912 can include an elastomerthat is a room temperature vulcanized (RTV) silicone. In someimplementations, the elastomeric lipseal 912 can include an elastomerthat is a perfluoroelastomer.

FIG. 9D shows a magnified view of FIG. 9C of the elastomeric lipsealpassing through a through-hole of the radially inwardly protrudingsurface of the cup bottom. As illustrated in FIGS. 9A-9D, theelastomeric lipseal 912 can be integrated with the cup bottom 901 bymolding or otherwise affixing the elastomeric lipseal 912 directly to(onto, over, into, etc.) the cup bottom 901, including the radiallyinwardly protruding surface 903 and its plurality of through-holes. Insome implementations, the cup bottom 901, or at least the radiallyinwardly protruding surface 903, may be treated chemically to enhanceadhesion. In some implementations, an adhesive or adhesion promoter maybe disposed between the elastomeric lipseal 912 and at least theradially inwardly protruding surface 903 of the cup bottom 901.

FIG. 9D shows dimensions of an example elastomeric lipseal 912. In FIG.9D, the elastomeric lipseal 912 includes a portion 926 that passesthrough a through-hole and encircles an inner lip 904 of a radiallyinwardly protruding surface 903. The elastomeric lipseal 912 disposed onthe radially inwardly protruding surface 903 can have a thickness ofabout 0.018 inches. The portion 926 of the elastomeric lipseal 912 thatpasses through the through-hole can have a diameter of about 0.026inches. The portion 926 of the elastomeric lipseal 912 that encirclesthe inner lip 904 underneath the inner lip 904 can have a thickness ofabout 0.015 inches. The portion 926 of the elastomeric lipseal 912 thatencircles the inner lip 904 facing outwards from the inner lip 904 canhave a width of about 0.01 inches. The portion 926 of the elastomericlipseal 912 that encircles the inner lip 904 directly above the innerlip 904 can have a height of about 0.035 inches and a width of about0.028 inches. Thus, the portion 926 of the elastomeric lipseal 912 canprotrude at a height more than the thickness of the elastomeric lipseal912 disposed on the radially inwardly protruding surface 903. Aperipheral region of a wafer can contact the elastomeric lipseal 912 atsuch a protrusion to seal the wafer from plating solution. Theprotrusion can provide a point of contact that the wafer is supported onand pressed against, where the protrusion can provide the sealing forceagainst the wafer to prevent the plating solution from entering. Theheight of such a protrusion can be about 0.017 inches. The total heightof the portion 926 of the elastomeric lipseal 912 from top to bottom canbe about 0.072 inches.

FIG. 9E shows a bottom perspective view of a portion the electroplatingcup assembly of FIG. 9A and including the elastomeric lipseal on theradially inwardly protruding surface of the cup bottom. The elastomericlipseal 912 can be affixed to both a top portion of the radiallyinwardly protruding surface 903 and a bottom portion of the radiallyinwardly protruding surface 903.

Whereas oftentimes the elastomeric lipseal or sealing element used toseal a wafer in an electroplating clamshell is a separate component thatis installed into the electroplating clamshell prior to anelectroplating operation, the present disclosure integrates theelastomeric lipseal and a cup bottom of the electroplating clamshellduring the manufacturing process. In some implementations, theelastomeric lipseal can be affixed to the cup bottom duringmanufacturing by adhesion, molding, or another suitable process thatinhibits the uncoupling of the elastomeric lipseal from the cup bottom.As such, the elastomeric lipseal may be viewed as a permanent orintegrated feature of the cup bottom rather than as a separate removablecomponent.

Manufacture of an Integrated Elastomeric Lipseal and Cup Bottom

FIG. 10 is a flowchart illustrating a method of forming a lipseal on aradially inwardly protruding surface of a cup bottom. The operations ina process 1000 may be performed in different orders and/or withdifferent, fewer, or additional operations.

A process 1000 can begin at block 1005, where a cup bottom is provided,the cup bottom being sized to hold a wafer and including a main bodyportion and a radially inwardly protruding surface. The radiallyinwardly protruding surface includes a plurality of through-holes.

In some implementations, the cup bottom is made of a relatively rigidmaterial. For example, the cup bottom can include a polymeric material,such as PPS or PEEK. In some implementations, the radially inwardlyprotruding surface includes between about 100 and 500 through-holes. Insome implementations, each of the through-holes can have a diameter ofbetween about 0.01 inches and 0.05 inches. In some implementations, adistance between an inner edge or inner lip of the cup bottom and acenter of the through-holes is between about 0.05 inches and 0.5 inches.In some implementations, a thickness of the radially inwardly protrudingsurface of the cup bottom at the location of the through-holes isbetween about 0.02 inches and 0.05 inches.

In some implementations, the process 1000 can further include treatingthe radially inwardly protruding surface of the cup bottom, prior toaffixing the elastomeric lipseal, with an agent that facilitatesadhesion between the elastomeric lipseal and the radially inwardlyprotruding surface of the cup bottom. The agent may chemically orphysically change the surface of the cup bottom by, for example,increasing roughness, applying or removing electrical charge, oxidizingor reducing chemical moieties, and/or passivating reactive moieties. Insome implementations, the agent can include a plasma or strong oxidizingacid, such as nitric acid, sulfuric acid, perchloric acid, persulfuricacid, etc.

In the alternative or in addition to the aforementioned treatment, theprocess 1000 can further include applying an adhesive, prior to affixingthe elastomeric lipseal, to the radially inwardly protruding surface ofthe cup bottom or the elastomeric lipseal to promote adhesion betweenthe radially inwardly protruding surface of the cup bottom and theelastomeric lipseal. Various types of adhesives or adhesion promotersmay be used to improve adherence of the elastomeric lipseal to theradially inwardly protruding surface, such as 1200 OS from Dow CorningCorporation of Midland, Mich.

At block 1010 of the process 1000, an elastomeric lipseal is affixed onthe radially inwardly protruding surface, where the elastomeric lipseal,when pressed against by the wafer, seals against the wafer to as todefine a peripheral region of the wafer from which plating solution issubstantially excluded during electroplating. Portions of theelastomeric lipseal pass through the plurality of through-holes. Suchportions may constitute pillars of elastomeric material. In someimplementations, such portions of the elastomeric lipseal passingthrough the plurality of through-holes can also extend around an inneredge or inner lip of the cup bottom. In some implementations, theelastomeric lipseal may encircle the inner edge or inner lip of the cupbottom.

In some implementations, affixing the elastomeric seal can includeproviding a mold in the shape of the elastomeric lipseal around aportion of the radially inwardly protruding surface, including theplurality of through-holes, delivering a lipseal precursor to the mold,and converting the lipseal precursor to the elastomeric lipseal.Accordingly, the elastomeric lipseal is formed in situ inside the cupbottom, for instance, by molding it directly into the cup bottom. Inthis approach, a chemical precursor (such as the lipseal precursor) tothe elastomeric lipseal is placed in the location of the cup bottomsurface where the elastomeric lipseal is to reside. The chemicalprecursor is processed so as to form the desired elastomeric lipseal,such as by polymerization, curing, or other mechanism that converts thechemical precursor into the formed elastomeric lipseal having thedesired final structural shape. Examples of curing agents can includecross-linking agents, elevated temperatures, and ultraviolet radiation.

In some implementations, affixing the elastomeric lipseal can includepre-forming the elastomeric lipseal into its desired final shape andthen integrating it with the rigid cup bottom. The pre-formedelastomeric lipseal is integrated with the radially inwardly protrudingsurface of the cup bottom during the manufacture of the cup assembly.This can be done by affixing the pre-formed elastomeric lipseal to theappropriate location on the cup bottom via adhesive, glue, etc. or someother appropriate affixing mechanism.

In some implementations, the process 1000 can further include applyingan electrical contact element on or proximate to the elastomericlipseal, where the electrical contact element contacts the wafer in theperipheral region when the elastomeric seals against the wafer so thatthe electrical contact element may provide electrical power to the waferduring electroplating. In some implementations, numerous parallelelectrical contact elements may be provided around the wafer and appliedto contact the wafer.

Through integrated manufacture of the cup assembly with its elastomericlipseal, the elastomeric lipseal can be formed more precisely into itsdesired shape, and positioned more precisely within the structure of thecup bottom of the cup assembly than what is generally achieved with themanufacture of the cup assembly and sealing elements as separatecomponents. This allows, in conjunction with the rigid support of thecup bottom, the precise locating of the portion of the elastomericlipseal which contacts the wafer. Accordingly, because less margin forpositioning error is required, sealing elements having reduced radialprofiles may be employed, which in turn, allows the sealing elements tobe designed for contacting the wafer within the cup assemblysignificantly closer to the wafer's edge, reducing the edge exclusionregion during electroplating operations.

System Controllers

In some implementations, a controller is part of a system, which may bepart of the above-described examples. Such systems can comprisesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a wafer pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor wafer or substrate. The electronics may be referred to asthe “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery andcirculation of electrolyte, temperature settings (e.g., heating and/orcooling), pressure settings, vacuum settings, electrical power settings,fluid delivery settings, positional and operation settings, wafertransfers into and out of a tool and other transfer tools and/or loadlocks connected to or interfaced with a specific system.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor wafer or to a system. The operationalparameters may, in some embodiments, be part of a recipe defined byprocess engineers to accomplish one or more processing steps during thefabrication of one or more layers, materials, metals, surfaces,circuits, and/or dies of a wafer.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with, coupled to the system, otherwisenetworked to the system, or a combination thereof. For example, thecontroller may be in the “cloud” or all or a part of a fab host computersystem, which can allow for remote access of the wafer processing. Thecomputer may enable remote access to the system to monitor currentprogress of fabrication operations, examine a history of pastfabrication operations, examine trends or performance metrics from aplurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process. In some examples, a remote computer (e.g. aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet. The remote computer mayinclude a user interface that enables entry or programming of parametersand/or settings, which are then communicated to the system from theremote computer. In some examples, the controller receives instructionsin the form of data, which specify parameters for each of the processingsteps to be performed during one or more operations. It should beunderstood that the parameters may be specific to the type of process tobe performed and the type of tool that the controller is configured tointerface with or control. Thus as described above, the controller maybe distributed, such as by comprising one or more discrete controllersthat are networked together and working towards a common purpose, suchas the processes and controls described herein. An example of adistributed controller for such purposes would be one or more integratedcircuits on a chamber in communication with one or more integratedcircuits located remotely (such as at the platform level or as part of aremote computer) that combine to control a process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor wafers.

As noted above, depending on the process step or steps to be performedby the tool, the controller may communicate with one or more of othertool circuits or modules, other tool components, cluster tools, othertool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

Lithographic Patterning

The apparatuses/processes described hereinabove may be used inconjunction with lithographic patterning tools or processes, forexample, for the fabrication or manufacture of semiconductor devices,displays, LEDs, photovoltaic panels and the like. Typically, though notnecessarily, such tools/processes will be used or conducted together ina common fabrication facility. Lithographic patterning of a filmtypically comprises some or all of the following steps, each stepenabled with a number of possible tools: (1) application of photoresiston a workpiece, i.e., substrate, using a spin-on or spray-on tool; (2)curing of photoresist using a hot plate or furnace or UV curing tool;(3) exposing the photoresist to visible or UV or x-ray light with a toolsuch as a wafer stepper; (4) developing the resist so as to selectivelyremove resist and thereby pattern it using a tool such as a wet bench;(5) transferring the resist pattern into an underlying film or workpieceby using a dry or plasma-assisted etching tool; and (6) removing theresist using a tool such as an RF or microwave plasma resist stripper.

Other Embodiments

Although illustrative embodiments and applications of this invention areshown and described herein, many variations and modifications arepossible which remain within the concept, scope, and spirit of theinvention, and these variations would become clear to those of ordinaryskill in the art after perusal of this application. Accordingly, thepresent embodiments are to be considered as illustrative and notrestrictive, and the invention is not to be limited to the details givenherein, but may be modified within the scope and equivalents of theappended claims.

1-24. (canceled)
 25. A lipseal comprising: a plurality of pillars ofelastomeric material passing through a plurality of through-holes of aradially inwardly protruding moment arm of a cup bottom; and aninterlocking portion of the elastomeric material surrounding an inneredge of the radially inwardly protruding moment arm, wherein theinterlocking portion connects with the plurality of pillars of theelastomeric material to encircle the inner edge of the radially inwardlyprotruding moment arm.
 26. The lipseal of claim 25, wherein theelastomeric material is disposed along a surface of the radiallyinwardly protruding moment arm of the cup bottom.
 27. The lipseal ofclaim 25, wherein the interlocking portion and the plurality of pillarsare connected to encircle the inner edge of the radially inwardlyprotruding moment arm to provide mechanical interlocking of theelastomeric material with the cup bottom.
 28. The lipseal of claim 25,wherein each of the plurality of pillars has a diameter between about0.01 inches and about 0.05 inches.
 29. The lipseal of claim 25, furthercomprising: a protruding portion of the elastomeric material thatprotrudes vertically from the inner edge of the radially inwardlyprotruding moment arm.
 30. The lipseal of claim 25, wherein a distancebetween an inner edge of the radially inwardly protruding moment arm anda center of the through-hole is between about 0.05 inches and 0.5inches.
 31. A ring-shaped cup bottom of an electroplating cup assembly,the ring-shaped cup bottom comprising: a main body portion; and aradially inwardly protruding moment arm connected to the main bodyportion, wherein the radially inwardly protruding moment arm comprises aplurality of through-holes.
 32. The ring-shaped cup bottom of claim 31,wherein the plurality of through-holes are configured to receiveportions of an elastomeric lipseal passing therethrough.
 33. Thering-shaped cup bottom of claim 32, wherein the radially inwardlyprotruding moment arm comprises an inner edge, wherein the inner edge isconfigured to receive the portions of the elastomeric lipseal passingthrough the plurality of through-holes so that the portions of theelastomeric lipseal surround the inner edge.
 34. The ring-shaped cupbottom of claim 33, wherein the elastomeric lipseal is mechanicallyinterlocked with the inner edge of the radially inwardly protrudingmoment arm.
 35. The ring-shaped cup bottom of claim 33, wherein adistance between the inner edge and a center of the through-holes isbetween about 0.05 inches and about 0.5 inches.
 36. The ring-shaped cupbottom of claim 31, wherein the cup bottom comprises a polymericmaterial.
 37. The ring-shaped cup bottom of claim 36, wherein thepolymeric material is PPS.
 38. The ring-shaped cup bottom of claim 31,wherein each of the through-holes has a diameter between about 0.01inches and about 0.05 inches.
 39. The ring-shaped cup bottom of claim31, wherein the radially inwardly protruding moment arm of the cupbottom comprises between about 100 through-holes and about 500through-holes.
 40. The ring-shaped cup bottom of claim 31, wherein theradially inwardly protruding moment arm is configured to support anelastomeric lipseal.